Thiazolineazetidinone-type compounds

ABSTRACT

This invention relates to novel thiazolineazetidinone-type compounds represented by the formula ##STR1## wherein R represents a hydrogen atom, alkyl group, alkyl group replaced with halogen atoms, methyl group replaced with substituted or unsubstituted phenyl groups, methyl replaced with halogen atoms, or trialkylsilyl group and Z represents O or Cl 2 .

This invention relates to thiazolineazetidinone-type compounds and particularly to thiazolineazetidinone-type compounds represented by the formula ##STR2## wherein R represents an alkyl group, alkyl group replaced with halogen atoms, methyl group replaced with substituted or unsubstituted phenyl groups, methyl group replaced with halogen atoms or trialkylsilyl group and Z represents O or Cl₂.

The compounds of this invention are useful as the intermediates for synthesizing β-lactam-type antibiotics.

Examples of the alkyl groups represented by R in the formula (1) are methyl, ethyl, butyl, hexyl and like lower alkyl groups, etc. Examples of the halogen atoms are chlorine, bromine, iodine, etc. Examples of the substituted phenyl groups are those substituted with alkyl, alkoxy, halogen, nitro and the like, etc. Examples of the alkyl and alkoxy groups as the foregoing substituents are lower alkyl groups and lower alkoxy groups, such as methyl, ethyl, butyl, propyl, hexyl, methoxy, butoxy, propoxy, etc. Examples of the trialkylsilyl groups are trimethylsilyl, triethylsilyl, dimethylmonobutylsilyl, monomethyldibutylsilyl, etc.

The compounds of the formula (1) can be prepared for example by electrolyzing a compound represented by the formula ##STR3## wherein R and Z are as defined above in a homogeneous or inhomogeneous solvent comprising water and an organic solvent in the presence of a halide and/or hydrohalogenic acid.

The compounds of the formula (2) to be used as the starting material in the foregoing process are those heretofore known and can be easily prepared for example by the process disclosed in J.A.C.S. 92 2575 (1970).

Organic solvents useful in the electrolysis of this invention include methyl acetate, ethyl acetate, butyl acetate, methyl formate, ethyl formate, ethyl propionate and like esters of carboxylic acids, diethyl ether, dibutyl ether, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether and like ethers, dichloromethane, chloroform, carbon tetrachloride, dibromoethane and like hydrocarbon halides, acetonitrile, butyronitrile and like nitriles, methanol, ethanol, isopropanol, butanol, tertiary-butanol and like alcohols, pentane, hexane, cyclohexane and like hydrocarbons, benzene, toluene, xylene, chlorobenzene, and like aromatic compounds, etc. These organic solvents are used singly or in mixture.

In the electrolysis of this invention, the organic solvents are employed as a rule in mixture with water. The proportions of the former to the latter are 1:100 to 100:1 preferably 1:20 to 2:1. The mixed solvent may be in homogeneous or inhomogeneous form.

Exemplary of useful halides to be used as a supporting electrolyte are sodium chloride, potassium chloride, lithium chloride and like alkali metal salts, magnesium chloride, barium chloride, calcium chloride and like alkaline earth metal salts, ammonium chloride, tetramethylammonium chloride, tetraethylammonium chloride, tetrabutylammonium chloride, and like chlorinated ammonium and quaternary ammonium salts. Also usable as such halides are bromides, fluorides and iodides thereof.

Hydrochloric acid is employable as the hydrohalogenic acid. In the hydrohalogenic acid and/or halide can be incorporated a mineral acid other than the hydrohalogenic acid, an organic acid. Typical examples of mineral acids are, for example, sulfuric acid, nitric acid, carbonic acid, potassium hydrogensulfate, sodium hydrogensulfate, phosphoric acid, etc. Useful organic acids include mono-carboxylic acid or dicarboxylic acid having 1 to 15 carbon atoms, organic sulfonic acid having 1 to 10 carbon atoms, etc. Specific examples of these acids are formic acid, acetic acid, propionic acid, butyric acid, tartaric acid, oxalic acid, citric acid, phthalic acid, malic acid, paratoluenesulfonic acid, etc.

The electrolysis of this invention can be carried out at a current density in the range of usually about 5 to about 500 mA/cm², preferably about 10 to about 50 mA/cm². Electrode materials are those usually used such as platinum, carbon, stainless steel, lead oxide and nickel. The electrolysis is conducted at a temperature between about -20° to about 100° C., preferably about -10° to about 50° C. The electrolytic reaction is feasible with or without a diaphragm.

The required electric charge is usually about 2 to about 50 F/mol, although variable depending on the shape of the electrolytic cell, the kind of electrodes, the concentration of the substrate, the reactivity of the substrate, etc. The application of current at the electric charge in this range gives contemplated compounds of the formula (1) with extremely high purity in a yield as high as 85 to 95%.

When electrolyzing a compound of the formula (2) wherein R is a methyl group replaced with substituted or unsubstituted phenyl groups, the hydrogen atom constituting the methyl group may be halogenated. Stated more specifically, when R is --CH(C₆ H₅)₂ as in Example 5 to be described later, the group is converted to --CCl(C₆ H₅)₂ in the electrolysis of this invention. The compounds of the invention include those thus obtained.

The compounds of the formula (1) are useful as intermediates for synthesizing β-lactam type antibiotics and can be prepared by a process given below.

This invention will be described below in detail with reference to examples.

EXAMPLE 1 ##STR5##

Into a reactor were placed 50 mg of methyl ester of 2-(3-benzoyl-7-oxo-4-thio-2,6-diazabicyclo[3,2,0]hept-2-en-6-yl)-3-methyl-3-butenoic acid serving as the starting material, 0.07 ml of con, sulfuric acid, 5 ml of methylene chloride and a solution of 1 g of sodium chloride in 3 ml of water. Electrolysis was conducted at 25° C. and 1.6 to 1.8 V by using platinum electrodes while applying current in an amount of 30 mA. Thereafter the reaction mixture was extracted with 30 ml of methylene chloride. The extract was washed successively with an aqueous solution of sodium sulfite, with an aqueous solution of sodium hydrogencarbonate and then with an aqueous solution of sodium chloride and subsequently was dried over anhydrous sodium sulfate. Then the solvent was removed, and 74 mg of a light yellow liquid was obtained. The liquid was subjected to silica gel column chromatography using an ethyl acetate-benzene mixture as the developer, producing 51 mg of contemplated compound in a yield of 93%.

IR 1780, 1745, 1660, 1600, 858 cm⁻¹

NMR(CDCl₃) 3.97 (3H, s, COOCH₃), 4.16 (2H, s, --CH₂ Cl), 5.23 (2H, d, J=4 Hz, C═CH₂), 5.55 (1H, s, CH--COOCH₃), 5.96 (1H, d, J=4 Hz, --CH), 6.37 (1H, d, J=4 Hz, --CH), 7.4-8.4 (5H, m, phenyl)

EXAMPLE 2 ##STR6##

The reaction schematically illustrated above was carried out by using 50 mg of the starting material in a manner similar to that of Example 1, giving 50.5 mg of contemplated compound in a 93.5% yield.

NMR(CDCl₃) 4.89 (2H, s, --CH₂ CCl₃), 4.16 (2H, s, --CH₂ Cl), 5.23 (2H, d, C═CH₂), 5.55 (1H, s, CH--COOCH₂ CCl₃)

EXAMPLE 3 ##STR7##

Into a reactor were placed a solution of 1 g of sodium chloride in 3 ml of water, 50 mg of the starting compound, 0.07 ml of con. sulfuric acid and 5 ml of methylene chloride. A procedure similar to that of Example 1 was conducted, giving 51.8 mg of contemplated compound. Yield 95%.

NMR(CDCl₃) 1.38 (9H, s, COO--t--C₄ H₉), 3.81 (2H, s, CH₂ Cl), 5.14 (2H, s, C═CH₂), 5.41 (1H, s, CHCOO--t--C₄ H₉), 7.3-7.9 (5H, m, phenyl)

EXAMPLE 4 ##STR8##

A procedure similar to that of Example 1 was repeated by using 50 mg of the starting compound shown above, giving 49.8 mg of contemplated compound. Yield 90.2%.

IR 1715 cm⁻¹

NMR(CDCl₃) 4.18 (2H, s, CH₂ Cl), 5.22 (2H, d, C═CH₂), 5.95 (1H, d, CH), 6.39 (1H, d, CH), 7.4-8.3 (5H, m, phenyl)

EXAMPLE 5 ##STR9##

A procedure similar to that of Example 1 was repeated by using 50 mg of the above starting compound, giving 51.8 mg of contemplated compound. Yield 91%. The compound thus obtained was identified by IR and NMR.

EXAMPLE 6 ##STR10##

A procedure similar to that of Example 1 was repeated by using 50 mg of the above starting compound, giving 49.8 mg of contemplated compound. Yield 92.8%.

NMR(CDCl₃) 5.05 (2H, s, ##STR11## 4.12 (2H, s, CH₂ Cl), 5.25 (2H, d, C═CH₂), 7.10-8.03 (4H, m, phenyl)

EXAMPLE 7 ##STR12##

Synthesis of methyl ester of 2-(3-dichlorophenylmethyl-7-oxo-4-thio-2,6-diazabicyclo[3,2,0]-hept-2-en-6-yl)-3-chloromethyl-3-butenoic acid.

An electrolyte was prepared by adding to a solution of 1 g of sodium chloride in 3 cc of water, 0.07 cc of con. sulfuric acid, 5 cc of methylene chloride and 50 mg of methyl ester of 2-(3-benzyl-7-oxo-4-thio-2,6-diazabicyclo[3,2,0]hept-2-en-6-yl-3-methyl-3-butenoic acid. Electrolysis was conducted at 25° C. and 1.6 to 1.8 V for 2 hours by using platinum plate electrodes (3 cm²) and passing constant current of 30 mA. Thereafter the reaction mixture was extracted with 30 ml of methylene chloride. The extract was washed successively with an aqueous solution of sodium sulfite, with an aqueous solution of sodium hydrogencarbonate and then with an aqueous solution of sodium chloride, and was dried over anhydrous sodium sulfate. The solvent was removed, and 74 mg of a light yellow liquid was obtained. The liquid was subjected to silica gel column chromatography using a 5:1 benzene-ethyl acetate mixture as the developer, producing 62.5 mg of contemplated compound. Yield 96%.

IR 1780, 1745 cm⁻¹

NMR (CDCl₃) 3.75 (3H, s, COOCH₃), 3.81 (2H, s, --CH₂ Cl) 5.14 (2H, s, C═CH₂), 5.41 (1H, s, --CHCOOCH₃), 6.05 (2H, s, --CH), 7.3-7.9 (5H, m, phenyl)

EXAMPLE 8

An electrolyte was prepared by adding 0.07 cc of con. sulfuric acid, 5 cc of ethyl acetate and 50 mg of the same starting material as used in Example 7 to a solution of 1 g of NaCl in 5 cc of water. Electrolysis was conducted at 25° to 27° C. and 1.8 to 1.9 V for 2 hours by passing 30 mA constant current. The reaction mixture was subsequently treated in a manner similar to that of Example 7, giving 61 mg of contemplated compound. Yield 93.5%. The compound thus obtained was identified by IR and NMR with the results identical with those of Example 7.

EXAMPLE 9 ##STR13##

A procedure similar to that of Example 7 was repeated by using 50 mg of the starting material, giving 61 mg of contemplated compound. Yield 95%.

NMR(CDCl₃) 1.38 (9H, s, COO--t--Bu), 3.85 (2H, s, --CH₂ Cl), 5.12 (2H, s, C═CH₂), 5.41 (1H, s, --CHCOO--t--Bu), 6.03 (2H, s, CH) 7.3-8.0 (5H, m, phenyl)

EXAMPLE 10 ##STR14##

A procedure similar to that of Example 7 was repeated by using 50 mg of the starting material, giving 56.3 mg of contemplated compound. Yield 91.5%.

NMR (CDCl₃) 4.04 (2H, s, CH₂ Cl), 4.75 (2H, s, CH₂ CCl₃), 5.18 (2H, s, C═CH₂), 5.54 (1H, s, CHCOOCH₂ CCl₃), 7.0-7.65 (5H, m, phenyl)

EXAMPLE 11 ##STR15##

A procedure similar to that of Example 7 was repeated by using 50 mg of the starting material, giving 59.0 mg of contemplated compound. Yield 88.9%.

IR 1715 cm⁻¹

NMR(CDCl₃) 4.20 (2H, s, CH₂ Cl), 5.28 (2H, d, C═CH₂), 5.92 (1H, d, CH), 6.42 (1H, d, CH), 7.5-8.4 (5H, m, phenyl)

EXAMPLE 12 ##STR16##

A procedure similar to that of Example 7 was repeated by using 50 mg of the starting material, giving 56.2 mg of contemplated compound. Yield 91.5%.

NMR (CDCl₃) 4.08 (2H, s, CH₂ Cl), 5.02 (2H, s, ##STR17## 5.23 (2H, d, C═CH₂), 7.10-8.05 (4H, m, phenyl) 

I claim:
 1. Thiazolineazetidinone-type compounds represented by the formula ##STR18## wherein R represents a hydrogen atom, a lower alkyl group, a lower alkyl group replaced with halogen atoms, CCl(C₆ H₅)₂, a trialkylsilyl group, methyl group replaced with phenyl groups, methyl groups replaced with substituted phenyl groups, said substituent being selected from the group consisting of methyl, ethyl, butyl, propyl, hexyl, methoxy, butoxy, propoxy, halogen and nitro and Z represents O or Cl₂.
 2. Thiazolineazetidinone-type compounds as defined in claim 1 in which R represents a hydrogen atom, or methyl, 2,2,2-trichloroethyl, t-butyl, diphenylmethyl, or p-nitrobenzyl group. 